Improvement in safety-valves



UNITED STATES PATENT JOEEroE i MATTHEW SoEANNAeE AND EDWARD SGEANNAGE, Jn., on BOSTON, MASS., ASSIGNoES To ScnANNAeE, BATE a oo., on SAME PLAGE.

IMPROVEMENT IN SAFETY-VALVES.

Specification forming partof Letters Patent No. 113,455, dated April 4, 1871.

To all whom it may concern:

Be it known that we, MATTHEW SoEAN- NAGE and EDWARD SCRANNAGEMJT., both of Boston, in the county of Suffolk and State of Massachusetts, have invented certain lmprovements in Safety-Valves, of which the following is a full, clear,and exact description, reference being had to the accompanying drawing, making part of this specification, in which- A Figures 1 and 2 are elevations of safetyvalves constructed in accordance with our invention; Figs. 3 and 4, central vertical sections through the same. l

Our invention has for its object to produce a compact safety-valve of simple construction, which is kept closed by the pressure of the steam, gas, or other agent, in contradistinction to one closed by the action of a sprin g or weight 5 and consists in a casing provided with a spring which is raised by the pressure of the steam or gas iu a manner Similar to that of a steamgage, the spring, on being raised to a predetermined height, opening the safety-valve by means of suitable connections and allowing the steam or gas to escape.

To enable others skilled in the art to understand and use our invention, we will proceed to describe the Vmanner in which we have carried it out.

In Figs. l and 3 of the said drawing, A represents a tight casing, which is intended to be secured at a to a pipe leading from a Steamboiler or gas-generator. Within the casing A is a flat coiled spring, b, which rests on a disk or diaphragm, c, of rubber, leather, or other suitable material, the upper Side ofthe outer portion of the spring bearing .against a ilange, 5, on the inside of the casing.

Connected with the lower portion of the casing A are two pipes, B C, the upper ends of which communicate with the interior of the casing D, within which is placed the safetyvalve E, which is kept down on its seat by the pressure of the steam 0r gas upon it.

The upper end of the casing D is intended to be closed by a screw-plug fitting into the thread d.

To the springb is secured a Spindle,c, which passes up through the casing A, and carries ure of the steam or gas the cap'f is brought into contact with the stem g, and as the surface-area of the diaphragm c is greater than that of the valve E, the latter is opened on,

the pressure of the steam or gas being increased.

The valve is Vmade to open and the steam or gas permitted to escape at different pressures by adjusting the height of the cap fon the spindle c.

It' preferred, the adjustable cap f may be screwed to the bottom of the stem g of the safety-valve, instead of to the top ot the spindle e; or the adjustable cap may be dispensed with, and some other device employed to vary the distance between the top of the spindle c and the stem of the valve.

In Figs. 2 and 4i is represented a modification of our invention, in which the adjustable cap on the top of the spindle connected with the spring is made to act upon one end of a lever, G, pivotedat t to a support, h, the opposite end of this lever acting upon. the stern of the Safety-valve, which is kept closed by the pressure ofthe steam or gas.

A light spiral spring, 7c, is employed to keep the valve up in vcontact with its seat when there is 11o steam or gas within the pipe K, which communicates with one end of the horizontal pipe L, at the opposite end of which is the casing A, containing the spring b, the horizontal pipe L being connected with the boiler or generator by means of a pipe, M.

4With the arrangement shown in Figs. l and 3 the surface-area of the diaphragm c must necessarily be greater than that of the safetyvalve E, otherwise the latter could not beraised by the steam or gas. This is not, however, essential where a'lever, G, is employed,

as the power exerted on the stem of the valve may be varied by changing the position ofthe fulcrum of the lever.'

We do not claim, broadly, the use of an elastic disk and a Spring as a means of indieating or of communicating pressure; nor do Vsafety-Valve, substantially in the manner de-t A We clainnv 1t as an equivalent for a piston in. a scribed.

differential safetyvalve. Witness our hands this 15th day of Decem- Omim ber, 1870.

- MATTHEW SGRANNAGE. What We claim as our lnvention and desire Y to secure by Letters Patent, is j EDWARD SGRANNAGE JR' A spring, b, :md diaphragm c,inc10sed With- Witnesses: in a casing, A, and connected with it spindle, W. J. CAMBRIDGE, e, with its adjusting-nut j', for operating :L N. W. STEARNS. 

